This invention relates to blends of aromatic polycarbonates with rubber-modified monovinylidene aromatic polymers.
The polycarbonates of dihydric phenols such as bisphenol-A which are described in U.S. Pat. No. 3,028,365 are known to be useful in the manufacture of molded plastic parts. Such resins are notably tough and have moderately high softening temperatures. Unfortunately, however, as a result of their relatively poor melt flow characteristics, such polymers are generally more difficult to mold. Also, such aromatic polycarbonates are relatively expensive materials. Previous attempts to improve the melt flow characteristics of these polycarbonates have generally involved incorporating a lower melting and less expensive polymer into the polycarbonate. See, for example, U.S. Pat. Nos. 3,130,177 and 3,239,582. The blends resulting from such attempts generally exhibit improved melt flow properties at the sacrifice of other desirable features such as heat resistance, impact strength and the like.
In view of the deficiencies of the conventional polycarbonates and blends thereof, it would be highly desirable to provide an economical polycarbonate composition which exhibits improved processibility while retaining or exceeding the desirable properties characteristic of polycarbonates such as impact strength and heat resistance.